Browsing by Subject "Plant growth"

Now showing 1 - 3 of 3
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    Developing Salt-Tolerant Sod Mixtures for Use as Roadside Turf in Minnesota
    (Center for Transportation Studies University of Minnesota, 2014-12) Friell, Joshua; Watkins, Eric; Horgan, Brian
    Failure of roadside grass installations due to high levels of road salt is a common occurrence in Minnesota. Several species that are not currently included in the MnDOT recommendations for these sites have performed well in low-input turfgrass evaluations in Minnesota and warranted evaluation for salt tolerance and suitability for roadside environments. The goal of this project was to develop a recommended mixture or a set of mixtures that provide salt-tolerant sod for roadsides. In the first part of this research, cultivars of cool-season turfgrass were assessed for their ability to establish and survive on roadsides in Minnesota. Concurrently, these grasses were evaluated in a hydroponic system in the greenhouse for salinity tolerance. Together, these studies identified several species and cultivars that were promising for use on Minnesota roadsides. These top-performing grasses were then evaluated in a series of mixtures in three research trials: (1) a roadside evaluation at two locations in Minnesota; (2) a sod strength trial planted at two locations in Minnesota; and (3) an acute drought evaluation utilizing an automated rainout shelter. From these results, we identified species that should be components of a salt-tolerant turfgrass mixture for use on roadsides in Minnesota. Mixtures that included high proportions of fine fescues, especially hard fescue and slender creeping red fescue, performed the best in our trials indicating that these species should be utilized in MnDOT recommendations for turf grown on roadsides.
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    Evaluation of the genetic potential of prairie junegrass (Koeleria macrantha) for use as a low-input turfgrass
    (2010-05) Clark, Matthew Daniel
    Prairie junegrass [Koeleria macrantha (Ledeb.) Shultes] is a perennial, shortgrass prairie species distributed throughout the Northern Hemisphere. This species demonstrates tolerance to many environmental stresses found in Minnesota. In June 2007, 48 K. macrantha accessions from the United States National Plant Germplasm System (NPGS) were grown and evaluated in two experiments; (i) seed production characteristics and (ii) turf quality characteristics in 2 locations (St. Paul, MN and Becker, MN). In the seed production experiment, seed was harvested in 2008, and significant variation was found among accessions for several seed production traits including harvest date, plant height, seedhead number, and seed yield. A significant correlation between seedhead number and seed yield was found, which can be utilized for indirect selection in the production nursery. Plant growth and seed yield were highest at the Becker location demonstrating the species’ preference for well drained soils. In the turf quality experiment, mowed space plants were evaluated from 2007- 2009, nineteen accessions at Becker and 30 accessions at St. Paul performed with an adequate turf quality rating of 5.0 or higher when averaged over the three-year study, suggesting the potential for use in low-input areas. Prairie junegrass from northern collection regions displayed the highest ratings in spring green-up which is an important turf trait in northern climates. There was a strong negative correlation between this trait and mowing quality at Becker (r = -0.44) and at St. Paul (r = -0.34). Several accessions demonstrated acceptable mowing quality and would be candidates for integration into a native prairie junegrass breeding program. In June 2007 a third experiment was conducted. Three hundred genotypes representing crossing blocks derived from Colorado, Nebraska, and Minnesota germplasm were grown and evaluated for turf quality characteristics in a randomized complete block design with five clonal replications at 2 locations (St. Paul and Becker) and evaluated for three years. Following establishment, plots received no supplemental irrigation or fertility and were mowed weekly to a height of 6.4 cm. Broad-sense heritability estimates were calculated on a clonal mean (Hc) and single plant (Hsp) basis for turf quality (Hc = 0.62, Hsp = 0.13), crown density (Hc = 0.55, Hsp = 0.09), mowing quality (Hc = 0.59, Hsp = 0.09), and genetic color (Hc=0.45, Hsp = 0.06). The heritability estimates indicate that selection for these traits should result in significant gains in germplasm improvement. Differences were observed for means and variances among clones, crossing blocks, and/or collection regions for many of the traits evaluated including rust (incidence and severity), spring green-up, plant height, lateral spread, vertical re-growth, and flowering traits. The positive correlations among some of these traits and those with moderate heritability estimates will allow for multi-trait selection in cultivar development. Rust (unknown Puccinia species) was present at both locations.
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    Understanding Cyanobacteria-based Biofertilizers in Soil-Water and Soil-Plant Systems
    (2021-10) Alvarez De La Hoz, Adriana
    Growing pressures to increase agricultural productivity amid rising environmental impacts and global climate threats call for critical strategies that preserve the soil resource and improve sustainability. Microalgae, including cyanobacteria, are emerging as promising platforms to enhance soil structure and fertility and reduce our reliance on chemical fertilizers. To advance applications, further understanding is needed with different strains, plants, agroecological regions and types of soil including Mollisols, which are among the most productive soils in the world. This dissertation reviewed aspects of microalgae that might be applied in agriculture and evaluated effects of soil inoculations with the dinitrogen (N2)-fixing cyanobacterium Anabaena cylindrica UTEX 1611 on a Mollisol from the U.S. Upper Midwest. First, a comprehensive literature review supported microalgae as renewable resources for the potential development of biofertilizers, organic fertilizers, biostimulants, biocontrol agents, and soil conditioners. Furthermore, experiments with cyanobacterial soil inoculations described effects on soil structure and nutrient dynamics, soil loss and water nutrient levels after high-intensity rain simulations, and soil mineralization of cyanobacterial biomass. The results revealed changes in soil structural components that might be resistant to wind and water erosion, potential for reducing rainfall-induced soil loss, and a gradual nutrient release from the cyanobacterial biomass. High-intensity rain simulations also indicated depth-related positive changes in soil microbial dynamics that persisted after consecutive rains. Finally, experiments with a local variety of spring wheat consistently evidenced improvements in soil nutrients, microbial biomass, and microbial activity, and demonstrated that cyanobacteria, and a mixture with a local green microalga, supplied nitrogen (N) to support plant growth and partially replace urea. These findings provide insights on the positive role cyanobacteria might have as resources to enhance the sustainability and resiliency of agricultural systems.